The game got great concept with very cool gameplay. Having a tutorial is neat and nice visual too. However, the difficulty is very high. The rotation with the mouse can sometimes cancel itself out.
One of the main issues I found, even if there is no issue with the controls, is the lack of resources, like slow XP generation and planets being expensive. One thing I tried was buying all Earth planets and spinning for them for the entire round, at most getting up to 200 XP, but all that got me was two extra planets, which destroyed themselves after use.
Stage 3 is the furthest I could get, but the difficulty spike got really high there. Still a good job! Just needs a bit of balancing in the numbers.